In optics, the production of aspherical surfaces entails implementing production means that are much more complex than the production of simple spherical surfaces. This production is all the more difficult if the surface is not of revolution. Now, in a large number of applications, and in particular in the field of instrumentation for astronomy, the optical combinations with mirrors require such surfaces. These are generally off-axis parabolic surfaces. Once the surface is produced, it is no longer possible to modify its form.
It is, these days, known practice to produce surfaces that can be deformed in a programmed manner. These systems are used notably to produce adaptive surfaces. To produce such a system, a set of actuators is arranged under the surface of the mirror to be deformed, which actuators act on the surface according to an analysis of a reference wave front until the desired surface is obtained. It will be understood that this technique requires complex analysis means and a large number of actuators.